Asa Miller has not only shared it's "iPhone app built with React Native for viewing houses for sale in the Northwest: Den" but has blogged his entirely experience of building it with React Native over a weekend:

My adventures with React Native

I was incredibly excited watching the ReactConf video when they announced React Native. After many frustrating attempts to create great user experiences with PhoneGap, I had started to believe that the dream of using web technologies for mobile apps was dead. I’ve been using React on the web heavily for the past year and ever since I first grokked the “react” way of doing things, I felt like this was the future of web development. And now after using React Native for a full project, I have the same feeling that React Native is the future of mobile app development. I don’t think it will replace Objective-C or Swift. There will always be things that are better done native than through javascript. But React’s method of building UI’s is the future. I think React Native is the perfect example of the Hybrid App model. Use native Objective-C for what it’s good at, and web technologies for what they’re good at.

Check den on GitHub

Den is an iPhone app built with React Native for viewing houses for sale in the NW from rmls.com. After being frsutrated with a site that hasn't changed since 2004, I decided to build a better viewing experince in the phone.

The app was built in a weekend (or so) by one designer and one developer.